WOLFRAM|DEMONSTRATIONS PROJECT

Spinning Mass with Variable Radius

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t
0
r
2
1
A small ball is attached to a string passing through a pipe as shown in the figure. The ball is initially spinning around in a circle of radius
r
1
with tangential velocity
v
1
(the instantaneous linear velocity at some point). When the string is pulled down, the velocity of the ball increases as a consequence of the conservation of angular momentum.